Guam Rail

The Guam rail, known locally and in Chamorro as ko'ko', is a small, terrestrial bird endemic to Guam in the Rallidae family. They are one of the island's few remaining endemic bird species. The species became extinct in the wild in the early 1980s when biologists captured the remaining wild population to establish a breeding program. They have since been successfully introduced to the nearby Rota and Cocos islands. In 2019, they became the second bird species to be reclassified by the International Union for the Conservation of Nature from Extinct in the Wild to Critically Endangered.